2-Cyano-3- or 4-(substituted amino)oxanilic acid derivatives

ABSTRACT

The 2-cyano-3-or 4-(substituted amino) oxanilic acid derivatives of the formula: ##STR1## in which the group ##STR2## appears in the designated 3- or 4- position and R is --H; an alkali metal;  +  NH 4  ; alkyl of 1 to 6 carbon atoms, inclusive; aralkyl of 7 or 8 carbon atoms; or cycloalkyl of 5 or 6 carbon atoms; 
     R 1  is --H or alkyl of 1 to 9 carbon atoms; 
     R 2  is --H, alkyl of 1 to 9 carbon atoms or cycloalkyl of 3 to 6 carbon atoms; 
     R 1  and R 2 , together, with the nitrogen atom to which they are attached, are aziridinyl, azetidinyl, pyrrolidinyl, piperidinyl, piperazinyl, 4-lower alkyl-piperazinyl, morpholino or thiomorpholino; 
     And pharmaceutically acceptable acid addition salts thereof are anti-allergic agents.

RELATED APPLICATIONS

This is a division of application Ser. No. 710,481 filed Aug. 4, 1976,now U.S. Pat. No. 4,054,591, and which is a continuation-in-part of Ser.No. 620,626, filed Oct. 3, 1975 now abandoned.

BACKGROUND OF THE INVENTION

Atopic allergic reactions are of the immediate hypersensitivity type asopposed to delayed hypersensitivity reactions, the latter being involvedin such things as tuberculin sensitivity, transplant rejection, contactdermatitis and the like. Commonly recognized clinical conditions knownto be at least in part due to atopic immediate hypersensitivityreactions, include seasonal and perennial allergic rhinitis (hay fever)and asthma, anaphylaxis, urticaria, conjunctivitis, angioaedema, eczema,various food and drug reactions and insect sting reactions. Thesubstances most frequently responsible for atopic allergic reactions areplant pollen, animal feathers and danders, dust, milk and wheat, whetherinhaled or injected. Atopic hypersensitivity is found in man, dog andother animals although its occurrence is exceptionally found in thelower animals.

Atopic (immediate hypersensitivity) reactions are characterized by theimmunopathologic mechanism, the elements of which are: (1) a specificimmunoglobulin (antibody; IgE in man, or homocytotropic antibody in therat) is produced; (2) it is fixed to the surface of a target cell; (3)an antigen or allergin combines with the cell-bound antibody, which (4)induces release or one or more pharmacologic mediators, which in turn(5) induces symptoms of clinical disease such as increased vascularpermeability, smooth muscle contraction, mucous gland hypersecretion,leukotaxis (especially eosinophilotaxis) and irritation of sensory nerveendings.

A compound which will interfere with the antigen-IgE reaction to preventthe release of mediators from the mast cell, or permit a non-productiveantigen-antibody reaction without release of mediators, of necessityblocks the atopic allergic reaction thereby avoiding the resultantchanges which are symptomatic of the disease.

The presence of antibodies associated with atopic reactions in the hostserum is established by the passive sensitization of the skin of anormal recipient, after injection of serum from a sensitized host into askin site followed by injection of antigen into the same area 24 hourslater, resulting in a local hive. This is commonly referred to as thePrausnitz-Kustner (P-K) reaction.

The antibody associated with atopic hypersensitivity possessesdistinctive features in that it does not in all forms precipitate withits antigen, fails to pass the placenta from mother to fetus, hasspecial affinity for the skin, frequently lacks specificity toward anindividual antigen in an individual sensitized by a variety of antigenicfactors and is usually labile at about 56° C. after 2 hours.

The homocytotropic antibody found in or induced in the rat is related infunction and reaction to immunoglobulin E (reagin or IgE) found in thehuman. The correlation between homocytotropic antibody in the rat andIgE in the human has been established through the common effectsobtained from chemical reactions, immunological reactions and drugresponses in the two species hosting those antibodies. In the human,reagin is the antibody responsible for atopic immediate hypersensitivereactions. In the rat, the homocytotropic antibody is responsible foratopic immediate hypersensitive reactions.

In theory, reagin influences the cell membrane of a mast cell byreacting with an antigen, to initiate the reaction(s) within the mastcell which ultimately releases a mediator such as Bradykinin, SRS-A(slow reacting substance-A), histamine, and other unknown substances.The mediator effects a change in surrounding cell wall permeabilitypermitting a rapid change in flow or exudance of mediator(s) from thecells, resulting in an allergic attack symptom. The various methodscommonly employed to relieve the symptoms of allergic attack, none ofwhich are considered to be quite acceptable, are to (1) avoid attack bythe antigen, (2) block the production of antibody with animmunosuppressant, (3) block the action of the mediators on the cellunder attack by administration of anti-histamines,anti-5-hydroxy-tryptamine (5-HT) or anti-inflammatories, or (4)stimulate and cell under attack to negate the action of the mediatorthrough the action of bronchodilators such as Isoprel® or a Xanthine.

The only commercial compound known to date to operate as ananti-allergic primarily by blocking reaction(s) within the mast cells,thereby preventing the production and release of mediators, is disodiumcromoglycate (INTAL®).

Disodium cromoglycate and compounds of that class are preventative inthe sense that they must be administered to the sensitized animal priorto the allergic attack to be effective. They are not effective after themediators have been released from the mast cells. Hence, their functionis in preventing the release of mediators and/or a productiveantibody-antigen reaction. As such, the rat PCA test (measuring theeffect of mediator release) may be used to establish a compound aseffective for all atopies because it establishes the diminished mediatorrelease values in terms of the decrease in allergic response of theanimal. The rat PCA test establishes the extent of mediator release frommast cells located in the rodent skin as a factor of the diminishedeffect on the skin of the test animal in relationship to the controlanimals.

The rat PCA (passive cutaneous anaphylaxis) test provides a classicprocedure for evaluating the efficacy of drugs of the INTAL classrelative to the response of the standard test animal resulting fromantigen antibody interaction and mediator release. Extrapolation from aneffect on the homocytotropic antibody of the rat to an effect onreaginic antibody (IgE) in the human is proper because of the wellestablished relationship between these antibodies.

With knowledge of the mechanism of activity of INTAL in blocking theproduction of chemical mediators resulting from an antigen-antibodyreaction and the variety of confirmed activities of INTAL in controllingor preventing immediate hypersensitivity reactions in man, as well asthe close relationship between the rat homocytotropic antibody and IgEin the human, coupled with the fact that INTAL is the standard now usedin the field for evaluating the efficacy of new anti-allergic compoundsfor atopic allergic reactions via the rat PCA test must lead to thepractical conclusion that compounds which are active in the rat PCA testcan, with very reasonable assurance, be projected as activeanti-allergic agents in man, dog, etc.

As new anti-allergics are being developed, their activity mechanism isrelated to that of INTAL as the standard because of its known activityin man and its activity in the rat PCA test. In this regard see Pfisteret al., J. Med. Chem., vol. 15, No. 10, pp. 1032-1035 (1972); Broughtonet al., Nature, vol. 251, pp. 650-652, Oct. 18, 1971; and Assem et al.,British Med. Journal, Apr. 13, 1974, pp. 93-95.

DESCRIPTION OF THE INVENTION

In accordance with this invention, there is provided a group of chemicalcompounds, useful for inhibiting development of the physical symptomsattending an atopic allergic reaction, presenting the formula: ##STR3##in which R is --H; an alkali metal; ⁺ NH₄ ; alkyl of 1 to 6 carbonatoms, inclusive; aralkyl of 7 or 8 carbon atoms; or cycloalkyl of 5 or6 carbon atoms;

R¹ is --H or alkyl of 1 to 9 carbon atoms;

R² is --H, alkyl of 1 to 9 carbon atoms or cycloalkyl of 3 to 6 carbonatoms; and

R¹ and R², together with the nitrogen atom to which they are attached,are aziridinyl, azetidinyl, pyrrolidinyl, piperidinyl, piperazinyl,4-lower alkyl-piperazinyl, morpholino or thiomorpholino;

and pharmaceutically acceptable acid addition salts thereof.

In the preceeding formula, the alkali metals contemplated for the group"R", are sodium, potassium or lithium. Embraced by the expression "alkylof 1 to 6 carbon atoms" are such alkyl groups as methyl, ethyl,n-propyl, i-proyl, n-butyl, secondary butyl, tertiary butyl, pentyl andhexyl. The expression "aralkyl of 7 or 8 carbon atoms" is intended toembrace the benzyl and phenethyl radicals. The comtemplated cycloalkylgroups of 5 or 6 carbon atoms embrace cyclopentyl as well as cyclohexyl.The groups representing R¹ and R² may be normal or secondary alkylcontaining from 1 to 9 carbon atoms each. Where R¹ and R² represent acyclic group with the nitrogen atom depicted in the structural formula,they are represented as dimethylene, trimethylene, tetramethylene,pentamethylene, or the 3-oxa, aza, or thia-pentamethylene radicals (oxy,thio or imino di-ethylene). In those situations where R¹ and R²represent a heterocyclic group containing nitrogen, it is preferred toprepare the compounds in the form of their non-toxic pharmaceuticallyacceptable acid addition salts for the purpose of separation andrecovery. Likewise, when R¹ and/or R² is hydrogen, that amino group isprotected during reaction with the chloro oxalic acid ester followedultimately by removal of the protecting group. For this purpose, anystandard protecting group known to the art may be employed, thetrimethylsilyl group being representative of the type of protectinggroup especially suitable for the purpose stated.

The expression, pharmaceutically acceptable acid addition salts, is usedto include the non-toxic acid addition salts which may be formed witheither organic or inorganic acids such as hydrochloric, hydrobromic,sulfuric, phosphoric, methane sulfonic, nitric, p-toluene sulfonic,acetic, citric, maleic, succinic acid and the like.

The preferred compounds from the standpoint of potency are those inwhich R¹ and R² are hydrogen or R¹ is lower alkyl and R² is hydrogen andthe amino group ##STR4## is in the 3-position.

The 3- or 4-substituted-2-cyanooxanilic acid compounds of this inventionare generally produced by condensing an appropriately substituted2-cyanoaniline with an activated oxalic acid half ester in which thesubstituent in 3- or 4-position is amino, alkylamino of 1 to 9 carbonatoms, dialkylamino of 1 to 9 carbon atoms in either alkyl moiety,cycloalkylamino of 5 to 6 carbon atoms, aziridinyl, azetidinyl,pyrrolidinyl, piperidinyl piperazinyl, 4-lower alkyl-piperazinyl,morpholino or thiomorpholino. By an activated oxalic acid half ester,Applicants embrace the acid halides, mixed anhydrides, azide, and thelike groups employed in the production of amidic linkages.

The 2-cyano group may be formed optionally via dehydration of acorrespondingly 2-carbamyl substituted precursor. Furthermore, a freeamino group in 3- or 4-position may be produced by reduction of a nitrosubstituent after condensation with said activated oxalic acid halfester. The free amino group may be then mono- or dialkylated with groupswhich are optionally cyclizable. Likewise, the final product ester issaponified with an appropriate base to afford an alkali metal orammonium salt.

The compounds of this invention have been demonstrated to relieveallergic manifestations when administered intraperitoneally and/ororally to sensitized rats.

The technique employed to establish the anti-allergic activity of thedisclosed compounds is reported in Immunology, vol. 16, pp. (749-760(1969) and involves four male Charles River rats (200-250 g. bodyweight) per group to provide a control, a host for administration of astandard anti-allergic compound (disodium cromoglycate) and animals forthe test compound. The rats are injected intracutaneously or theirshaved backs with sera from rats immunized with egg albumin andpertussis vaccine. Twenty-four hours after the initial injections, thetest compound is administered intraperitoneally or orally at a maximumdosage level of 200 milligrams per kilogram host body weight. Fiveminutes later 1 milliliter of a 0.5 percent solution of Evans blue dyeand 8 milligrams of egg albumin is injected intravenously. After 40minutes, the animal is sacrificed and the bleb size on its back ismeasured. The mean bleb size for the animals administered the testcompound is calculated and the percent inhibition is determined bycomparison with the control animal.

Although the mechanism by which the compounds of this invention functionis not absolutely known, applicants have found that the compounds ofthis invention, in a manner believed to be similar to the function ofINTAL, block reaction(s) in the mast cell leading to the production andrelease of mediators. The compounds of this invention permit theoccurrence of a non-productive antigen-antibody interaction byeffectively blocking the IgE type reaction. In sum, the compounds ofthis invention block the release of mediators commonly resulting fromthe antigen antibody reaction as exemplified in a passive cutaneousanaphylaxis test (PCA) using rat homocytotropic antibody--a knowncorrelate of human reaginic antibody.

By analogy to disodium cromoglycate and its activity correlation betweenstandard test animals, domestic animals and man, the compounds of thisinvention have been established as anti-allergic agents suitable for useas inhalants or by oral or parenteral administration.

Thus, the compounds of this invention are useful for suppressingallergic manifestations of atopic immediate sensitivity in warm-bloodedhuman and non-human animals, the latter including domesticated animalssuch as the mouse, rat, hamster, gerbil, dog, cat, sheep, goat, horse,cow, and the like, by administering an effective amount of one or moreof the compounds disclosed in ths application by oral, topical,intraperitoneal, intramuscular or intravenous routes. The compounds ofthis invention may be administered in conjunction with known compoundseffecting antihistaminic, anti-hypertensive, analgesic, central nervoussystem depressant, immunosuppressive, anti-serotonin, anti-Bradykinin orendocrinological responses. In addition, those conventional adjuvantsknown to the art may be combined with the anti-allergics of thisinvention to provide compositions and solutions for administrativepurposes, although it is considered desirable and feasible to employ theanti-allergics as neat or pure compounds without additives other thanfor purposes of providing suitable pharmaceutical solution or liquid orvapor suspensions.

The effective dose range in test animals has been established to be fromabout 0.01 milligrams per kilogram to a dosage resulting insubstantially 100 percent prevention of the allergic response at 200milligrams per kilogram host body weight, or less.

As an inhalant, the dose is 2 milligrams or less, administered as neededprior to attack. Thus, the dosage contemplated for human oral orintraperitoneal use based upon the potency of the compound administeredlies from about 1 milligram to 2 grams, preferably 5 milligrams to about1.5 grams in unit dosage form to be administered when necessary and tothe degree of the desired response, in single or plural doses under theguidance of a physician.

Regarding the dosage to be used in the treatment of a specific atopicallergic reaction, the subjective observations of the attendingphysician are determinative. The human dose, like the dose for the dog,depends upon the specific allergy being treated, the size, age, responsepattern and severity of the known allergic attack in the specificpatient. No unusual skill is involved in establishing the most desirabledose size and regimen for a specific patient because the loss orsuppression of the symptom is apparent to both the patient and thephysician. The effective amount of the anti-allergic compoundadministered must be empirically determined subjectively.

Illustrative of the compounds of this invention, which are orally activeare 2-cyano-3-(dimethylamino)oxanilic acid ethyl ester, demonstratingoral activity equivalent to 54% inhibition at 5 milligrams per kilogramhost body weight; 67% inhibition at 25 milligrams per kilogram host bodyweight and 73% inhibition at 100 milligrams per kilogram host bodyweight, as well as 2 -cyano-3-(4-methyl-1-piperazinyl)oxanilic acidethyl ester hydrochloride which effects a 77% inhibition upon oraladministration of 25 milligrams per kilogram host body weight.Illustrative of the compounds of this invention possessing anti-allergicactivity upon intraperitoneal administration is2-cyano-3-(1-piperidinyl)oxanilic acid ethyl ester which affords 93%inhibition at 200 milligrams per kilogram host body weight; the twocompounds mentioned in the preceding sentence presenting respectively,93% inhibition at 200 milligrams per kilogram host body weight and 88%inhibition at 200 milligrams per kilogram host body weight. As notedsupra, the preferred compounds as those in which the amino group appearsin 3-position as the free amino group or lower alkylamino group. Thesecompounds have been found to effect 100% inhibition with as low as 0.10milligrams per kilogram dosage administered intravenously with thesodium salt of [2-cyano-3-(methylamino)phenylamino]oxoacetic acid.

EXAMPLE 1 [2-Cyano-3-(Dimethylamino)Phenylamino]Oxoacetic Acid EthylEster

To a solution of 9.7 g. of 2,6-dinitrobenzonitrile and 6.1 g. ofdimethylamine hydrochloride in 100 ml. of dimethylformamide is added 6g. of potassium hydroxide in 20 ml. of water. The solution is stirredfor 4 hours, poured into ice water and the product,2-dimethylamino-6-nitrobenzonitrile, is filtered and dried, m.p.112°-116° C.

Analysis for: C₉ H₉ N₃ O₂ --Calculated: C, 56.54; H, 4.75; N, 21.98.Found: C, 56.28; H, 4.77; N, 21.77.

To a suspension of 5.7 g. of 2-dimethylamino-6-nitrobenzonitrile in 20ml. of methanol and 17 ml. of concentrated hydrochloric acid is added5.3 g. of iron powder in portions. The mixture is stirred for 1/2 hour,diluted with 200 ml. of water and extracted with methylene chloridewhich is dried and evaporated in vacuo to yield crude2-amino-6-dimethylaminobenzonitrile.

To a solution of 3.4 g. of crude 2-amino-6-dimethylaminobenzonitrile and1.6 g. of pyradine in 50 ml. of methylene chloride at 0° is addeddropwise 2.7 g. of ethyl oxalyl chloride in 25 ml. of methylenechloride. The solution is stirred at 0° C. for 3 hours, warmed to roomtemperature and water is added. The organic phase is separated, driedand evaporated to give a yellow solid which is recrystallized frombenzene-hexane to yield 3.2 g. of the title compound, m.p. 124°-126° C.

Analysis for: C₁₃ H₁₅ N₃ O₃ --Calculated: C, 59.76; H, 5.79; H, 16.08.Found: C, 59.47; H, 5.47; N, 16.08.

EXAMPLE 2 [2-Cyano-3-(1-Piperidinyl)Phenylamino]Oxoacetic Acid EthylEster

To a solution of 19.3 g. of 2,6-dinitrobenzonitrile in 300 ml. ofdimethylformamide is added 25.5 g. of piperidine and the resultingsolution is warmed to 85° C. and kept at that temperature until thereaction is complete. The reaction mixture is poured into water, theproduct, 2-nitro-6-(1-piperidinyl)benzonitrile, is filtered and dried,m.p. 119°-121° C.

Analysis for: C₁₂ H₁₃ N₃ O₂ --Calculated: C, 62.32; H, 5.67; N, 18.17Found: C, 62.32; H, 5.82; N, 18.26.

The 2-nitro-6-(1-piperidinyl)benzonitrile prepared in the precedingparagraph is converted to 2 -amino-6-(1-piperidinyl)benzonitrile by ironreduction following the procedure of Example 1.

The title compound is produced by reaction of2-amino-6-(1-piperidinyl)benzonitrile with ethyl oxalyl chloride, m.p.98°-100° C.

Analysis for: C₁₆ H₁₉ N₃ O₃ --Calculated: C, 63.77; H, 6.36; N, 13.94.Found: C, 63.76; H, 6.37; N, 13.76.

EXAMPLE 3 [2-Cyano-3-(4-Methyl-1-Piperazinyl)Phenylamino]Oxacetic AcidEthyl Ester Hydrochloride

Following the procedure presented in the first paragraph of Example 2,with the exception that N-methylpiperazine is substituted forpiperidine, 2-(4-methyl-1-piperazinyl)-6-nitrobenzonitrile is prepared,m.p. 126°-129° C.

Analysis for: C₁₂ H₁₄ N₄ O₂ --Calculated: C, 58.52; H, 5.73; N, 22.75.Found: C, 58.65; H, 5.87; N, 22.78.

To a solution of 4.92 g. of2-(4-methyl-1-piperazinyl)-6-nitrobenzonitrile in 11 ml. of concentratedhydrochloric acid is added 3.4 g. of iron powder. The mixture is stirredfor 30 minutes, poured into ice water and the pH is adjusted to 12.Methylene chloride is added, the whole mixture is filtered throughcelite, the methylene chloride is separated, dried and evaporated togive solid, crude product,2-amino-6-(4-methyl-1-piperazinyl)benzonitrile.

A mixture 3.96 g. of crude2-(4-methyl-1-piperazinyl)-6-aminobenzonitrile, 2.74 g. of ethyl oxalylchloride is stirred for 2 hours at room temperature, poured into 1.68 g.of sodium bicarbonate in 25 ml. of water and stirred for 5 minutes. Theorganic layer is separated, dried and evaporated. The residue isdissolved in diethyl ether-ethanol, saturated diethyl ether-hydrogenchloride is added and the product is allowed to crystallize to give thepure title compound, m.p. 204°-206° C. (dec.).

Analysis for: C₁₆ H₂₀ N₄ O₃ . HCl--Calculated: C, 54.56; H, 6.00; N,15.88; Cl, 10.05. Found: C, 54.53; H, 6.31; N, 15.90; Cl, 10.08.

Following the general preparative procedures exemplified in thepreceding examples, by varying the amine reactant (HNR¹ R²) employed inthe displacement reaction with 2,6-dinitrobenzonitrile, reducing theremaining nitro substituent to afford the reactive amino group andfinally coupling that product with an oxalyl chloride ester, there isafforded a family of 2-cyano-3- or 4-(substituted amino)oxanilic acidesters which may be directly saponified to afford a salt, or readilyhydrolyzed under mild conditions to yield the corresponding oxanilicacids which are in turn readily converted to the corresponding saltsupon reaction with a desired base.

Various amines, HNR¹ R², employed in the synthesis of the anti-allergiccompounds of this invention and the final products, employing ethyloxalyl chloride in each instance as representative of the simply oxalylester reactants employed in the synthesis, are:

    ______________________________________                                        NHR.sup.1 R.sup.2                                                             ______________________________________                                        R.sup.1      R.sup.2       Ethyl Ester of                                     ______________________________________                                         1. H        CH.sub.3      2-cyano-3-(methyl-                                                            amino)oxanilic acid                                2. CH.sub.3  CH.sub.3      2-cyano-3-(dimethyl-                                                          amino)oxanilic acid                                3. CH.sub.3                                                                                 ##STR5##     2-cyano-3-(iso- propylmethyl- amino)oxanilic                                  acid                                               4. H         CH.sub.2 CH.sub.3                                                                           2-cyano-3-(ethyl-                                                             amino)oxanilic acid                                5. CH.sub.2 CH.sub.3                                                                       CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3                                                         2-cyano-3-(ethyl-                                                             butylamino)oxanilic                                                           acid                                               6. H                                                                                        ##STR6##     2-cyano-3-(sec- butylamino)oxanilic acid           7. CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3                                                     CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3                                                         2-cyano-3-(dibutyl-                                                           amino)oxanilic acid                                8. H         heptyl        2-cyano-3-(heptyl-                                                            amino)oxanilic acid                                9. H         hexyl         2-cyano-3-(hexyl-                                                             amino)oxanilic acid                                10. H                                                                                       ##STR7##     2-cyano-3-(isobutyl- amino)oxanilic acid            ##STR8##                                                                     ______________________________________                                        11. 1-pyrrolidinyl     2-cyano-3-(1-pyrrol-                                                          idinyl)oxanilic acid                                   12. 1-piperidinyl      2-cyano-3-(piper-                                                             idino)oxanilic acid                                    13. 4-methyl-1-piperazinyl                                                                           2-cyano-(4-methyl-1-                                                          piperazinyl)oxanilic                                                          acid                                                    ##STR9##              Final Product Ethyl Ester of                           ______________________________________                                        14. morpholino         2-cyano-3-(morpho-                                                            lino)oxanilic acid                                     15. thiomorpholino     2-cyano-3-(thio-                                                              morpholino)oxanilic                                                           acid                                                   16. 1-azetidine        2-cyano-3-(1-azetidi-                                                         nyl)oxanilic acid                                      17. 1-aziridine        2-cyano-3-(1-aziridi-                                                         nyl)oxanilic acid                                      ______________________________________                                    

EXAMPLE 4 [2-Cyano-4-(Dimethylamino)Phenylamino]Oxoacetic Acid EthylEster

To a solution of 4.6 g. of[2-(aminocarbonyl)-4-(dimethylamino)phenylamino]oxoacetic acid ethylester in 130 ml. of chloroform at 0° C. is added 2 ml. of phosphorusoxychloride and 13 ml. of triethylamine. The reaction is stirred at roomtemperature until complete (approximately 6 days). Water is added, thepH is adjusted to about 5 and the organic layer is separated, dried andevaporated. The product is recrystallized from ethanol, m.p. 150°-152°C.

Analysis for: C₁₃ H₁₅ N₃ O₃ --Calculated: C, 59.76; H, 5.79; N, 16.08.Found: C, 59.76; H, 6.02; N, 15.91.

[2-(Aminocarbonyl)-4-(dimethylamino)phenylamino]oxacetic acid ethylester is prepared by oxalation of 2-amino-5-dimethylaminobenzamide withethyl oxalyl chloride as in Example 1, m.p. 203°-205° C.

Analysis for: C₁₃ H₁₇ N₃ 0₄ --Calculated: C, 55.90; H, 6.14; N, 15.05.Found: C, 56.12; H, 6.23; N, 15.08.

2-Amino-5-dimethylaminobenzamide is obtained by treatment of5-dimethylaminoisatoic anhydride hydrochloride with 1N ammoniumhydroxide in a manner similar to the procedure of R. P. Staizer and E.C. Wagner, J. Org. Chem., 13, 347 (1948).

5-Dimethylaminoisatoic anhydride hydrochloride is obtained by treatmentof the corresponding anthranilic acid with phosgene in a manneridentical to that given in J. H. Sellstedt et al., J. Med. Chem., 18,926 (1975) for 3,5-dimethyl anthranilic acid, m.p. 256°-258° C. (dec).

Analysis for: C₁₀ H₁₀ N₂ O₃ . HCl--Calculated: C, 49.49; H, 4.57; N,11.55; Cl, 14.61. Found: C, 49.15; H, 4.54; N, 11.10; Cl, 14.57.

5-Dimethylaminoanthranilic acid is known, R. A. Rossi and H. E.Bertorello, An. Assoc. Quim. Argent., 55, 227 (1967).

EXAMPLE 5 [3-Amino-2-Cyanophenylamino]Oxoacetic Acid Ethyl Ester

The title compound is prepared by reduction of[3-nitro-2-cyanophenylamino]oxoacetic acid ethyl ester with 10% Pd. oncharcoal and with cyclohexene in ethanol according to the procedure ofI. D. Entwistle and R. A. W. Johnstone, J. Chem. Soc., Perkin I, 1300(1975). The crude product is chromatographed on silica gel withchloroform and recrystallized from ethanol, m.p. 133°-136° C.

Analysis for: C₁₁ H₁₁ N₃ O₃ --Calculated: C, 56.64; H, 4.76; N, 18.02.Found: C, 56.58; H, 4.64; N, 18.20.

[3-Nitro-2-cyanophenylamino]oxoacetic acid ethyl ester is prepared bytreatment of 2-amino-6-nitrobenzonitrile with ethyl oxalyl chloride asin Example 1, m.p. 111°-113° C.

Analysis for: C₁₁ H₉ N₃ O₅ --Calculated: C, 50.19; H, 3.45; N, 15.97.Found: C, 50.11; H, 3.44; N, 15.99.

2-Amino-6-nitrobenzonitrile is prepared as follows:

2,6-Dinitrobenzonitrile (19.3 g.) is dissolved in methanol (400 ml.) anddioxane (250 ml.) at reflux. To this is added conc. hydrochloric acid(60 ml.) followed by iron powder (18 g.) in portions. The mixture isleft at reflux for 1 hr., and is evaporated to dryness. Water is added,the resultant solid is filtered off, dried and extracted with hot ethylacetate. After filtration through Celite®, the product is allowed tocrystallize, m.p. 196°-198° C.

Analysis for: C₇ H₅ N₃ O₂ --Calculated: C, 51.54; H, 3.09; N, 25.76.Found: C, 51.39; H, 3.01; N, 25.68.

EXAMPLE 6 [3-(Methylamino)-2-Cyanophenylamino]Oxoacetic Acid Ethyl Ester

Oxalation of 2-amino-6-methylaminobenzonitrile as in Example 1 gives thetitle compound, m.p. 137°-139° C.

Analysis for: C₁₂ H₁₃ N₃ O₃ --Calculated: C, 58.29; H, 5.30; N, 17.00.Found: C, 58.13; H, 5.32; N, 16.94.

2-Amino-6-methylaminobenzonitrile is prepared by iron reduction of2-methylamino-6-nitrobenzonitrile as in Example 1.

2-Methylamino-6-nitrobenzonitrile is prepared as follows:

to 19.3 g. of 2,6-dinitrobenzonitrile in 150 ml. of dimethylformamide at85° C. is added 25 ml. of 40% aqueous methylamine. The mixture is heatedfor 1 hour, poured into ice water and the product is removed byfiltration, m.p. 203°-206° C.

Analysis for: C₈ H₇ N₃ O₂ --Calculated: C, 54.23; H, 3.99; N, 23.72.Found: C, 54.24; H, 3.70; N, 24.02.

EXAMPLE 7 [2-Cyano-3-(Ethylamino)phenylamino]Oxoacetic Acid Ethyl Ester

Crude 2-amino-6-ethylaminobenzonitrile is oxalated as in Example 1 togive the title compound, m.p. 99°-102° C.

Analysis for: C₁₃ H₁₅ N₃ O₃ --Calculated: C, 59.76; H, 4.79; N, 16.08.Found: C, 59.35; H, 5.89; N, 15.88.

Crude 2-amino-6-ethylaminobenzonitrile is prepared by iron reduction of2-ethylamino-6-nitrobenzonitrile as in Example 1.

2-ethylamino-6-nitrobenzonitrile is obtained by displacement on2,6-dinitrobenzonitrile with ethylamine as in Example 6, m.p. 114°-116°C.

Analysis for: C₉ H₉ N₃ O₂ --Calculated: C, 56.54; H, 4.75; N, 21.98.Found: C, 56.73; H, 4.75; N, 21.73. EXAMPLE 8

[3-(Butylamino)-2-Cyanophenylamino]Oxoacetic Acid Ethyl Ester

This material is prepared following the procedure of Example 1, byoxalation of 2-amino-6-butylaminobenzonitrile, m.p. 101°-105° C.

Analysis for: C₁₅ H₁₉ N₃ O₃ --Calculated: C, 62.26; H, 6.62; N, 14.52.Found: C, 62.03; H, 6.42; N, 14.55.

2-amino-6-butylaminobenzonitrile is obtained by iron reduction as inExample 1.

2-butylamino-6-nitrobenzonitrile is obtained by the usual displacementreaction using butylamine, m.p. 72°-74° C.

Analysis for: C₁₁ H₁₃ N₃ O₃ --Calculated: C, 60.26; H, 5.98; N, 19.15.Found: C, 60.38; H, 6.09; N, 19.06.

EXAMPLE 9 [3-(Ethylmethylamino)-2-Cyanophenylamino]Oxoacetic Acid EthylEster

Treatment of 2-amino-6-(ethylmethylamino)benzonitrile with oxalylchloride as in Example 1 gives the product, m.p. 75°-78° C.

Analysis for: C₁₄ H₁₇ N₃ O₃ --Calculated: C, 61.08; H, 6.22; N, 15.26.Found: C, 60.77; H, 6.21; N, 15.34.

The amine is obtained by the usual iron reduction.2-(ethylmethylamine)-6-nitrobenzonitrile is obtained by displacementwith ethylmethylamine, m.p. 60°-63° C.

Analysis for: C₁₀ H₁₁ N₃ O₂ --Calculated: C, 58.53; H, 5.40; N, 20.48.Found: C, 58.84; H, 5.48; N, 20.81.

EXAMPLE 10 [2-Cyano-3-(Methylisopropylamino)Phenylamino]Oxoacetic AcidEthyl Ester

The usual oxalation as in Example 1 of2-amino-6-(methylisopropylamino)benzonitrile gives the title compound,m.p. 64°-67° C.

Analysis for: C₁₅ H₁₉ N₃ O₃ --Calculated: C, 62.26; H, 6.62; N, 14.52.Found: C, 62.30; H, 6.65; N, 14.53.

2-amino-6-(methylisopropylamino)benzonitrile is obtained by ironreduction as in Example 1.

2-(methylisopropylamino)-6-nitrobenzonitrile is obtained by the usualsubstitution using methylisopropylamine, m.p. 70°-72° C.

Analysis for: C₁₁ H₁₃ N₃ O₂ --Calculated: C, 60.26; H, 5.98; N, 19.15.Found: C, 60.21; H, 5.93; N, 19.19.

EXAMPLE 11 [2-Cyano-3-(Pyrrolidinyl)Phenylamino]Oxoacetic Acid EthylEster

Oxalation of 2-amino-6-pyrrolidinylbenzonitrile as in Example 1 givesthe title compound, m.p. 138°-141° C.

Analysis for: C₁₅ H₁₇ N₃ O₃ --Calculated: C, 62.70; H, 5.96; N, 14.63.Found: C, 62.81; H, 5.98; N, 14.61.

2-amino-6-pyrrolidinylbenzonitrile is prepared by iron reduction of thecorresponding nitro derivative as in Example 1, m.p. 112°-114° C.

Analysis for: C₁₁ H₁₃ N₃ --Calculated: C, 70.56; H, 7.00; N, 22.44.Found: C, 70.51; H, 6.71; N, 22.50.

2-nitro-6-pyrrolidinylbenzonitrile is prepared by the usual displacement(Example 6) using pyrrolidine, m.p. 111°-113° C.

Analysis for: C₁₁ H₁₁ N₃ O₂ --Calculated: C, 60.82; H, 5.10; N, 19.35.Found: C, 61.04; H, 5.14; N, 19.59.

EXAMPLE 12 [2-Cyano-3-(Morpholinyl)Phenylamino]Oxoacetic Acid EthylEster

This is prepared from 2-amino-6-norpholinylbenzonitrile and ethyloxalylchloride in the usual manner, m.p. 115°-117° C.

Analysis for: C₁₅ H₁₇ N₃ O₄ --Calculated: C, 59.39; H, 5.65; N, 13.86.Found: C, 59.21; H, 4.76; N, 13.69.

2-amino-6-morpholinylbenzonitrile is prepared by reduction of2-(4-morpholinyl)-6-nitrobenzonitrile as in Example 1, m.p. 157°-160° C.

Analysis for: C₁₁ H₁₃ N₃ O--Calculated: C, 65.00; H, 6.45; N, 20.68.Found: C, 64.81; H, 6.35; N, 20.79.

2-(4-morpholinyl)-6-nitrobenzonitrile is prepared by displacement withmorpholine as in Example 6, m.p. 152°-155° C.

Analysis for: C₁₁ H₁₁ N₃ O₃ --Calculated: C, 56.65; H, 4.76; N, 18.02.Found: C, 56.95; H, 4.82; N, 18.35.

EXAMPLE 13 [2-Cyano-3-(4-Morpholinyl)Phenylamino]Oxoacetic Acid1-Methylpropyl Ester

This material is prepared as in Example 12 using sec-butyloxalylchloride instead of ethyl oxalyl chloride, m.p. 108°-111° C.

Analysis for: C₁₇ H₂₁ N₃ O₄ --Calculated: C, 61.62; H, 6.39; N, 12.68.Found: C, 61.42; H, 6.71; N, 12.95.

The following sodium salts are all prepared by the same procedure:

The oxoacetic acid ethyl ester is dissolved in ethanol at reflux exactlyone equivalent of 5.9 N sodium hydroxide is added and the solution isallowed to cool. The resulting solid is filtered, washed with ethanoland dried to give the sodium salt.

EXAMPLE 14 [2-Cyano-3-(Methylamino)phenylamino]Oxoacetic Acid SodiumSalt, 2/5 hydrate, 1/5 Ethanolate

m.p. 272°-275° C.(dec).

Analysis for: C₁₀ H₈ N₃ O₃ ·1/5 EtoH . 2.5 H₂ O--Calculated: C, 48.49;H, 3.91; N, 16.31. Found: C, 48.70; H, 3.82; N, 16.29.

EXAMPLE 15 [2-Cyano-3-(Ethylmethylamino)Phenylamino]Oxoacetic Acid,Sodium Salt, 7/10 Hydrate

m.p. 90°-94° C.

Analysis for: C₁₂ H₁₂ N₃ O₅ Na·7/10 H₂ O--Calculated: C, 51.14; H, 4.79;N, 14.91. Found: C, 51.01; H, 4.65; N, 14.99.

EXAMPLE 16 [3-(Butylamino)-2-Cyanophenylamino]Oxoacetic Acid, SodiumSalt

m.p. 252°-254° C.

Analysis for: C₁₃ H.sub..4 N₃ O₃ Na--Calculated: C, 55.12; H, 4.98; N,14.83. Found: C, 54.82; H, 4.80; N, 14.59.

EXAMPLE 17 [2-Cyano-3-(4-Morpholinyl)Phenylamino]Oxoacetic Acid, SodiumSalt, 4/10 Hydrate

m.p. 170° C. (shrink), 240° C. (dec.).

Analysis for: C₁₃ H₁₂ N₃ O₄ Na . 4/10 H₂ O--Calculated: C, 51.28; H,4.24; N, 13.80. Found: C, 51.35; H, 4.28; N, 13.91.

EXAMPLE 18 (4-Amino-2-Cyanophenylamino)Oxoacetic Acid Ethyl Ester

5.0 g. of (2-cyano-4-nitrophenylamino)oxoacetic acid ethyl ester in 150ml. of ethanol and 0.4 g. of 10% Pd/C is hydrogenated until hydrogenuptake ceases. The reaction mixture is filtered through Celite®,evaporated to dryness and the solid is recrystallized from ethanol, 4.1g., m.p. 137°-139° C.

Analysis for: C₁₁ H₁₁ N₃ O₃ --Calculated: C, 56.65; H, 4.76; N, 18.02.Found: C, 56.49; H, 4.94; N, 18.09.

(2-cyano-4-nitrophenyl)oxoacetic acid ethyl ester is prepared by theusual ethyl oxalation of 2-amino-5 nitrobenzonitrile as in Example 1,m.p. 137°-319° C.

Analysis for: C₁₁ H₉ N₃ O₅ --Calculated: C, 50.19; H, 3.45; N, 15.97.Found: C, 49.99; H, 3.55; N, 15.98.

The oxalyl chloride ester employed in the synthesis of the compounds ofthis invention is preferable the ethyl ester, the sec-butyl ester or thecyclohexyl ester. However, other simple esters are similarly applicable,producing the corresponding ester products with unchanged biologicalactivity, although assimilation by the host may vary somewhat. Thus, theesters initially produced may be lower alkyl (e.g. methyl, ethyl,propyl, i-propyl, butyl, sec-butyl, amyl, sec-amyl, hexyl, etc.);aralkyl (e.g. benzyl, Phenethyl, etc.); or cycloalkyl (e.g. cyclopentyl,cyclohexyl, etc.). Thus, the esters produced as part of this inventionembrace esters in which the hydrocarbon moiety of the alcohol is alkylof 1 to 5 carbon atoms, hydrocarbonic aralkyl of 7 or 8 carbon atoms orcycloalkyl of 5 or 6 carbon atoms.

What is claimed is:
 1. A compound of the formula: ##STR10## in which Ris --H; an alkali metal; ⁺ NH₄ ; alkyl of 1 to 6 carbon atoms,inclusive; benzyl or phenethyl; or cycloalkyl of 5 or 6 carbon atoms;andR¹ and R² together, with the nitrogen atom to which they areattached, are aziridinyl, azetidinyl, pyrrolidinyl, piperidinyl,piperazinyl, 4-lower alkyl-piperazinyl, morpholino or thiomorpholino;ora pharmaceutically acceptable acid addition salt thereof.
 2. A compoundof claim 1 in which the group ##STR11## is in 3-position.
 3. Thecompound of claim 1 which is 2-cyano-3-(1-piperidinyl)oxanilic acid, analkali metal salt, the ammonium salt, or an alkyl ester containing from1 to 6 carbon atoms in the alkoxy moiety.
 4. The compound of claim 1which is 2-cyano-3-(4-methyl-1-piperazinyl)oxanilic acid, an alkalimetal salt, the ammonium salt, or an alkyl ester containing from 1 to 6carbon atoms in the alkoxy moiety.
 5. The compound of claim 1 which is[2-cyano-3-(pyrrolidinyl)phenylamino]oxoacetic acid, an alkali metalsalt, the ammonium salt, or an alkyl ester containing from 1 to 6 carbonatoms in the alkoxy moiety.
 6. The compound of claim 1 which is[2-cyano-3-(morpholinyl)phenylamino]oxoacetic acid, an alkali metalsalt, the ammonium salt, or an alkyl ester containing from 1 to 6 carbonatoms in the alkoxy moiety.